Genetic risk factors for rheumatoid arthritis differ in Caucasian and Korean populations

Potential role of soluble CD40 receptor in chronic inflammatory diseases

The CD40 receptor and its ligand CD154 are widely expressed in various immune-competent cells. Interaction of CD154 with CD40 is essential for B-cell growth, differentiation, and immunoglobulin class switching. Many other immune-competent cells involved in innate and adaptive immunity communicate through this co-stimulatory ligand-receptor dyad. CD40-CD154 interaction is involved in the pathogenesis of numerous inflammatory and autoimmune diseases. While CD40 and CD154 are membrane-bound proteins, their soluble counterparts are generated by proteolytic cleavage or alternative splicing. This review summarises current knowledge about the impact of single nucleotide polymorphisms in the human CD40 gene and compensatory changes in the plasma level of the soluble CD40 receptor (sCD40) isoform in related pro-inflammatory diseases. It discusses regulation patterns of the disintegrin metalloprotease ADAM17 function leading to ectodomain shedding of transmembrane proteins, such as pro-inflammatory adhesion molecules or CD40. The role of sCD40 as a potential biomarker for chronic inflammatory diseases will also be discussed.

The risk assessment of uveitis after COVID-19 diagnosis: A multicenter population-based study

Reports on uveitis after COVID-19 have been limited. Our objective was to examine the risk of uveitis among COVID-19 patients. This was a retrospective cohort study based on the TriNetX platform. The exposure group was patients with positive laboratory test result for SARS-CoV-2 and the comparison group was those tested negative for COVID-19 throughout the study period. The endpoint is the new diagnoses of uveitis. This study composed of 2 105 424 patients diagnosed with COVID-19 (55.4% female; 62.5% white; mean age at index 40.7 years) and 2 105 424 patients (55.4% female; 62.4% white; mean age at index 40.7 years) who never had COVID-19. There was significantly increased risk of new diagnosis of uveitis since the first month after diagnosis of COVID-19 compared with matched controls (HR: 1.18, 95% CI: 1.03-1.34) up to 24 months (HR: 1.16, 95% CI: 1.09-1.22). Our findings strengthen those previously raised by case series with a larger and multicenter study. We found that uveitis was significantly associated with COVID-19 infection. Our findings reiterate the need for careful investigation as well as increased awareness from ophthalmologists in considering the possibility of COVID-19 in vulnerable patients with new presentation of uveitis.

Progression of pre-rheumatoid arthritis to clinical disease of joints: Potential role of mesenchymal stem cells

Rheumatoid arthritis (RA) related autoimmunity is developed at mucosal sites due to the interplay between genetic risk factors and environmental triggers. The pre-RA phase that leads to anti-citrullinated protein antibodies, rheumatoid factor, and other autoantibodies spread in the systemic circulation may not affect articular tissue for years until a mysterious second hit triggers the localization of RA-related autoimmunity in joints. Several players in the joint microenvironment mediate the synovial innate and adaptive immunological processes, eventually leading to clinical synovitis. There still exists a gap in the early phase of RA pathogenesis, i.e., the progression of diseases from the systemic circulation to joints. The lack of better understanding of these events results in the inability to answer questions about why only after a certain point of time the disease appears in joints and why in some cases, it simply remains latent and doesn't affect joints at all. In the current review, we focused on the immunomodulatory and regenerative role of mesenchymal stem cells and associated exosomes in RA pathology. We also highlighted the age-related dysregulations in activities of mesenchymal stem cells and how that might trigger homing of systemic autoimmunity to joints.

Analysis of PTPN22 -1123 G>C, +788 G>A and +1858 C>T Polymorphisms in Patients with Primary Sjögren's Syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune exocrinopathy characterized by lymphocytic infiltration, glandular dysfunction and systemic manifestations. Lyp protein is a negative regulator of the T cell receptor encoded by the tyrosine phosphatase nonreceptor-type 22 (PTPN22) gene. Multiple single-nucleotide polymorphisms (SNPs) in the PTPN22 gene have been associated with susceptibility to autoimmune diseases. This study aimed to investigate the association of PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A), rs2476601 (+1858 C>T) with pSS susceptibility in Mexican mestizo subjects.

METHODS

One hundred fifty pSS patients and 180 healthy controls (HCs) were included. Genotypes of PTPN22 SNPs were identified by PCR-RFLP. PTPN22 expression was evaluated through RT-PCR analysis. Serum anti-SSA/Ro and anti-SSB/La levels were measured using an ELISA kit.

RESULTS

Allele and genotype frequencies for all SNPs studied were similar in both groups (p > 0.05). pSS patients showed 17-fold higher expression of PTNP22 than HCs, and mRNA levels correlated with SSDAI score (r² = 0.499, p = 0.008) and levels of anti-SSA/Ro and anti-SSB/La autoantibodies (r² = 0.200, p = 0.03 and r² = 0.175, p = 0.04, respectively). Positive anti-SSA/Ro pSS patients expressed higher PTPN22 mRNA levels (p = 0.008), with high focus scores by histopathology (p = 0.02). Moreover, PTPN22 expression had high diagnostic accuracy in pSS patients, with an AUC = 0.985.

CONCLUSIONS

Our findings demonstrate that the PTPN22 SNPs rs2488457 (-1123 G>C), rs33996649 (+788 G>A) and rs2476601 (+1858 C>T) are not associated with the disease susceptibility in the western Mexican population. Additionally, PTPN22 expression may be helpful as a diagnostic biomarker in pSS.

Tofacitinib for the treatment of rheumatoid arthritis: a real-world study in China

Tofacitinib has only been available in China for 2 years to treat rheumatoid arthritis (RA). Our purpose was to compare real-world effectiveness of tofacitinib with that of disease-modifying anti-rheumatic drugs (DMARDs) in Chinese patients with RA. The records of patients with RA treated at Guangdong Provincial People's Hospital between July 2017 and September 2019 were retrospectively reviewed. Patients were divided into those treated with tofacitinib, biological DMARDs (bDMARDs), and conventional synthetic DMARDs (csDMARDs). Clinical disease activity index (CDAI), simplified disease activity index (SDAI), health assessment questionnaire-disability index (HAQ-DI), visual analog scale (VAS) pain score, patient global assessment of disease activity (PtGA), physician global assessment of disease activity (PhGA), and swollen joint and tender joint count were compared among the groups up to 12 months of treatment. A total of 150 patients were included: 63 were treated with tofacitinib, 48 with bDMARDs, and 39 with csDMARDs. Tofacitinib was first-line treatment in 26.98% of patients, second-line treatment in 49.21%, and third-line treatment in 26.98%. Patients in the tofacitinib group had significantly higher disease duration (6.11 ± 6.97 years) than those in the other groups. All disease indices in the three groups decreased with time, indicating improvement of symptoms, with no differences among the groups at 12 months. Tofacitinib appeared to improve symptoms more rapidly than other treatments; however, differences in disease indices were not significant. This real-world study suggests that tofacitinib is rapidly effective and that the effects are sustained after 12 months in Chinese patients with RA.

Inflammasome and Its Therapeutic Targeting in Rheumatoid Arthritis

Inflammasome is a cytoplasmic multiprotein complex that facilitates the clearance of exogenous microorganisms or the recognition of endogenous danger signals, which is critically involved in innate inflammatory response. Excessive or abnormal activation of inflammasomes has been shown to contribute to the development of various diseases including autoimmune diseases, neurodegenerative changes, and cancers. Rheumatoid arthritis (RA) is a chronic and complex autoimmune disease, in which inflammasome activation plays a pivotal role in immune dysregulation and joint inflammation. This review summarizes recent findings on inflammasome activation and its effector mechanisms in the pathogenesis of RA and potential development of therapeutic targeting of inflammasome for the immunotherapy of RA.

Systematic investigation on the anti-rheumatoid arthritis material basis and mechanism of Juan Bi Tang. Part 1: Integrating metabolic profiles and network pharmacology

Previously, our cooperative team confirmed the chemical composition and anti-rheumatoid arthritis (RA) efficacy of Juanbi-Tang (JBT), a clinically and historically used traditional Chinese medicine formula, in two model animals. In this study, we developed an in vivo-in silico strategy to elucidate the anti-RA material basis and mechanism of JBT. With the aid of high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (HPLC-Q-TOF), the metabolic profiles were investigated in normal and collagen-induced arthritis RA rats following oral administration of JBT. Based on the absorbed constituents in RA rats, network pharmacology was employed to predict the anti-RA mechanisms, followed by molecular docking validation. Consequently, there were 18 absorbed compounds with 6 chemical structures, which were absolutely identified by matching with standard compounds in plasma, and 17 generated metabolites involved of 7 biotransformation pathways, including glucuronidation, sulfation, hydroxylation, deglycosylation, methylation, taurine, and glycine conjugation. Moreover, RA disease affected the absorption and metabolism of the constituents in JBT, given the undetected 2 absorbed compounds and 4 metabolites in RA rats. The analysis of network pharmacology indicated that those absorbed compounds in JBT may fight against RA through the MAPK, FoxO, and Rap1 pathways. Molecular docking also validated these results. Overall, this is the first study to describe the metabolic profiles of JBT-treated healthy and RA rats, and it provides a possible anti-RA mechanism through multiple absorbed compounds and targets by network pharmacology.

Excess mortality persists in patients with rheumatoid arthritis

OBJECTIVES

To investigate the causes and risk of death in a large cohort of Korean patients with rheumatoid arthritis (RA).

METHODS

Patients in the Hanyang BAE (Bae registry of Autoimmune diseases for Epidemiology) RA cohort who fulfilled the American College of Rheumatology criteria were analyzed. A total of 2355 patients were enrolled from October 2001 to December 2015. Mortality data were derived by linking with data from the Korean National Statistical Office. Standardized mortality ratio was estimated by dividing observed deaths by expected number of deaths in the general population.

RESULTS

Over the observation period, 225 deaths were reported. Total age- and sex-adjusted standardized mortality ratio was 1.65 (95% confidence interval 1.44-1.87). The most common cause of death was malignancy (40 cases; 17.8%), followed by respiratory disease (38 cases; 16.9%) and cardiovascular disease (32 cases; 14.2%). Mortality rate and causes of death differed according to year and age of RA onset. Compared with survivors, individuals who died were more likely to be male, smokers, diagnosed with RA at an older age, and to have long disease duration, higher erythrocyte sedimentation rate and C-reactive protein, higher rheumatoid factor positivity rate, more severe radiographic damage, and more comorbidities.

CONCLUSION

The mortality rate of patients with RA remains higher than that of the general population. Therefore, to improve the survival of patients with RA, attention should be paid to the management of comorbidities as well as to the RA itself.

Current and novel therapeutic targets in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a multifactorial disease characterized by synovitis, cartilage destruction, bone erosion, and periarticular decalcification, finally results in impairment of joint function. Both genetic and environmental factors are risk factors in the development of RA. Unwanted side effects accompany most of the current treatment strategies, and around 20-40% of patients with RA do not clinically benefit from these treatments. The unmet need for new treatment options for RA has prompted research in the development of novel agents acting through physiologically and pharmacologically relevant targets. Here we discuss in detail three critical pathways, Janus kinase/signal transducer and activator of transcription (JAK/STAT), Th17, and hypoxia-inducible factor (HIF), and their roles as unique therapeutic targets in the field of RA. Some of the less developed but potential targets like nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome and histone deacetylase 1 (HDAC1) are also discussed.

Role of Protein Tyrosine Phosphatase (PTPN22) Gene [C1858T] Functional Variant in Genetic Susceptibility of Psoriatic Arthritis in Kuwaiti Arabs

Background:

Psoriatic arthritis (PsA) is a chronic, systemic inflammatory arthritic disease characterized by joint inflammation that is associated with cutaneous psoriasis, and can lead to pain, swelling, or stiffness in one or more joints. It results from a complex interplay between genetic, immunologic and environmental factors. A functional variant [C1858T] in the protein tyrosine phosphatase (PTPN22) gene, which encoded Arg620Trp in the lymphoid protein tyrosine phosphatase (LYP) has been shown to be a negative regulator of T-cell activation.

Objective:

The objective of this study was to investigate an association between PTPN22 gene [C1858T] functional variant and PsA in Kuwaiti patients.

Methods:

We have investigated the association of PTPN22 gene functional variant in 102 Kuwaiti patients with psoriatic arthritis and compared it to that in 214 healthy controls. The genotypes for the PTPN22 gene [C1858T] variant were determined by using a PCR-RFLP method and confirmed by DNA sequence analysis.

Results:

The frequency of homozygous variant genotype (TT) was found to be significantly higher in PsA patients compared to that in the controls (p <0.0001). Collectively, the variant genotype was detected in homozygous and heterozygous combinations in 30% patients (p <0.0001) compared to 16% in the controls. The frequency of variant genotype was found to be highest in the early-onset PsA patients (age >25-34y). No correlation was detected between the variant genotype (TT) and gender in the Kuwaiti PsA patients.

Conclusion:

Our data show a significant association of PTPN22 gene functional variant [C1958T] with PsA in Kuwaiti patients and highlight its role in determining the genetic susceptibility along with other factors.

Associations of TRAF1/C5 rs10818488 and rs3761847 polymorphisms with genetic susceptibility to rheumatoid arthritis: a case-control study and updated meta-analysis

The results on associations of tumor necrosis factor (TNF)-receptor associated factor 1/complement component 5 (TRAF1/C5) rs10818488 and rs3761847 polymorphisms with rheumatoid arthritis (RA) are controversial, thus this study was performed to examine whether the aforementioned polymorphisms were associated with RA in a Chinese population. Furthermore, an updated meta-analysis was conducted. The polymorphisms were genotyped in 328 Chinese RA patients and 449 healthy controls. Studies examining the association of TRAF1/C5 rs10818488 and/or rs3761847 polymorphism with RA were exhaustively searched. No significant difference in either genotype or allele distribution between RA patients and controls was found. The updated meta-analysis was conducted based on 19 articles including the present study. A significant association of RA with TRAF1/C5 rs10818488 polymorphism G allele in Europeans (OR = 0.843, 95% CI = 0.730-0.975, p = 0.021) and in Asians (OR = 1.070, 95% CI = 1.009-1.136, p = 0.024) was found. Additionally, a significant association of RA with TRAF1/C5 rs10818488 polymorphism G allele under the recessive model in Asians (OR = 1.129, 95% CI = 1.023-1.246, p = 0.016) and in Africans (OR = 0.657, 95% CI = 0.507-0.851, p = 0.001) was found. Only a borderline significant association of RA with TRAF1/C5 rs3761847 polymorphism A allele was found in Europeans. Non-significant associations of RA with TRAF1/C5 rs10818488 and rs3761847 polymorphisms were found in our study. The updated meta-analysis results demonstrate that TRAF1/C5 rs10818488 polymorphism is associated with RA in Europeans, Asians and Africans, and TRAF1/C5 rs3761847 polymorphism is associated with RA in Europeans with borderline significant evidence.

Association between PTPN22-1123G/C and susceptibility to rheumatoid arthritis: A systematic review and meta-analysis

BACKGROUND

The incidence of rheumatoid arthritis (RA) varies greatly among different ethnic groups, suggesting genetic susceptibility. The several genetic variants of protein tyrosine phosphatase, non-receptor type 22 (PTPN22-1123G/C, rs2488457) have been widely examined. We systematically evaluated the association of PTPN22-1123 and RA risk by pooling the related studies conducted in different races.

METHODS

Literature was searched using PubMed, EMBASE, Cochrane Library, Korean scientific database, Chinese medical databases, and the Indian medical database to identify eligible studies for determining the association of PTPN22-1123 and RA risk. The association was assessed in five genetic random effects models including the allelic (AG), recessive (RG), dominant (DG), homozygous (HMG), and heterozygous (HTG) genetic models. Subgroup analyses stratified by ethnicity (Asians and non-Asians) were assessed.

RESULTS

A total of 10 articles were selected that met the criteria including Hardy-Weinberg equilibrium. Subjects included 14 186 healthy controls and 5735 with RA. The AG, RG, DG, and HMG genetic models showed no heterogeneity, but the HTG model showed heterogeneity. AG and RG did not exhibit publication bias in any of the studies including Asian and non-Asian subgroups. The overall effect of PTPN22-1123 on RA risk in all genetic random models showed significant positive associations (AG: odds ratio [OR]: 1.24; CI: 1.08-1.42; P = 0.002; RG: OR: 1.35; CI: 1.15-1.59; P = 0.0003; DG: OR: 1.42; CI: 1.09-1.85; P = 0.009; HMG: OR: 1.69; CI: 1.22-2.34; P = 0.002). A significant association when pooling the studies was only revealed in non-Asians (P < 0.05), but no significant relationship was shown in Asians.

CONCLUSIONS

People with C allele in PTPN22-1123 increased the risk of RA only in non-Asians.

The Contribution of PTPN22 to Rheumatic Disease

One of the unresolved questions in modern medicine is why certain individuals develop a disorder such as rheumatoid arthritis (RA) or lupus, while others do not. Contemporary science indicates that genetics is partly responsible for disease development, while environmental and stochastic factors also play a role. Among the many genes that increase the risk of autoimmune conditions, the risk allele encoding the W620 variant of protein tyrosine phosphatase N22 (PTPN22) is shared between multiple rheumatic diseases, suggesting that it plays a fundamental role in the development of immune dysfunction. Herein, we discuss how the presence of the PTPN22 risk allele may shape the signs and symptoms of these diseases. Besides the emerging clarity regarding how PTPN22 tunes T and B cell antigen receptor signaling, we discuss recent discoveries of important functions of PTPN22 in myeloid cell lineages. Taken together, these new insights reveal important clues to the molecular mechanisms of prevalent diseases like RA and lupus and may open new avenues for the development of personalized therapies that spare the normal function of the immune system.

Sequencing of the MHC region defines HLA-DQA1 as the major genetic risk for seropositive rheumatoid arthritis in Han Chinese population

OBJECTIVE

The strong genetic contribution of the major histocompatibility complex (MHC) region to rheumatoid arthritis (RA) has been generally attributed to human leukocyte antigen (HLA)-DRB1. However, due to the high polymorphisms and linkage disequilibrium within MHC, it is difficult to define novel and/or independent genetic risks using conventional HLA genotyping or chip-based microarray technology. This study aimed to identify novel RA risk variants by performing deep sequencing for MHC.

METHODS

We first conducted target sequencing for the entire MHC region in 357 anticitrullinated protein antibodies (ACPA)-positive patients with RA and 1001 healthy controls, and then performed HLA typing in an independent case-control cohort consisting of 1415 samples for validation. All study subjects were Han Chinese. Genetic associations for RA susceptibility and severity were analysed. Comparative modelling was constructed to predict potential functions for the newly discovered RA association variants.

RESULTS

HLA-DQα1:160D conferred the strongest and independent susceptibility to ACPA-positive RA (p=6.16×10^-36, OR=2.29). DRβ1:37N had an independent protective effect (p=5.81×10^-16, OR=0.49). As predicted by comparative modelling, the negatively charged DQα1:160D stabilises the dimer of dimers, thus may lead to an increased T cell activation. The negatively charged DRβ1:37N encoding alleles preferentially bind with epitope P9 arginine, thus may result in a decreased RA susceptibility.

CONCLUSIONS

We provide the first evidence that HLA-DQα1:160D, instead of HLA-DRB1*0405, is the strongest and independent genetic risk for ACPA-positive RA in Han Chinese. Our study also illustrates the value of deep sequencing for fine-mapping disease risk variants in the MHC region.

The Protein Tyrosine Phosphatase Nonreceptor 22 (PTPN22) R620W Functional Polymorphism in Psoriasis

Background:

Psoriasis is a complex autoimmune disease caused by the interaction of genetic and environmental factors. PTPN22 gene polymorphism has been reported to affect psoriasis susceptibility; however, no data are available for Middle Eastern populations.

Objective:

The aim of this study was to investigate the association of PTPN22 (1858C/T) R620W polymorphism with psoriasis in a Saudi cohort.

Methods:

Saudi subjects (n = 306) including patients with psoriasis (n = 106) and matched controls (n = 200) were studied for PTPN22 variants using tetra-primer amplification refractory mutation system-polymerase chain reaction method. The frequencies of alleles and genotypes of PTPN22 (1858C/T) polymorphism were compared between patients and controls.

Results:

The frequency of CT genotype of PTPN22 (1858C/T) polymorphism was significantly higher, whereas that of CC genotype was lower in patients with psoriasis than in controls (P < .001, relative risk [RR] = 7.151). The homozygous genotype TT was absent in both the patients and healthy controls. The frequency of allele T encoding tryptophan (W) was significantly increased (P < .001, RR = 5.76), whereas that of allele C encoding arginine (R) decreased in psoriasis cases as compared with controls (P < .001, RR = 0.173) indicating that individuals carrying allele T are more susceptible to psoriasis than noncarriers.

Conclusions:

PTPN22 (1858C/T) polymorphism is positively associated with susceptibility of psoriasis in Saudis and can be developed as biomarker for evaluating psoriasis risk. However, further studies on PTPN22 polymorphism in larger samples from different geographical areas and ethnicity are warranted.

Associative role of HLA-DRB1 SNP genotypes as risk factors for susceptibility and severity of rheumatoid arthritis: A North-east Indian population-based study

Rheumatoid arthritis (RA) is a complex, multifactorial, systemic autoimmune disease. Reports are suggestive of the role of HLA especially HLA-DRB1 alterations in RA pathogenesis. Existing data involving different geographical populations on the role of alterations in specific locus of HLA-DRB1 in RA susceptibility and severity are equivocal, with no data available from ethnically distinct North-east Indian population, where RA cases are alarmingly increasing. This study aimed to evaluate the association of HLA-DRB1 gene SNPs (rs13192471, rs660895 and rs6457617) with susceptibility and severity of RA in an ethnically distinct North-east Indian population. Whole blood was collected from clinically characterized RA cases (satisfying the American College of Rheumatology 1987 criteria) (n = 123) and community-based age and sex-matched healthy controls (n = 156) with informed consent. The HLA-DRB1 SNP analysis was performed for all the RA and control cases using ARMS-PCR using case and control genomic DNA as template. Statistical analysis was performed by SPSSv13.0 software. The HLA-DRB1 rs660895 showed both wild (AA) and heterozygote (AG) genotype but the heterozygote allele was found to be associated with reduced risk of RA compared to controls [OR = 0.531, p = .024]. The difference in distribution of rs6457617 polymorphism between RA and control cases was comparable [OR = 0.525, p = .079]. Significantly higher distribution of variant rs13192471 genotype was observed in RA cases (69.92%) compared to controls (46.75%) (p < .001) and was associated with increased risk of susceptibility to RA [OR = 2.576, p < .001] compared to controls, as well as progression to severity in RA cases [OR = 2.404, p = .048]. Combinatorially also, the presence of rs13192471 variant genotype was associated with increased risk of RA susceptibility [OR = 8.267, p = .026] and RA severity [OR = 3.647, p = .280]. Alterations in HLA-DRB1 are associated with RA susceptibility. HLA-DRB1 rs13192471 SNP plays a critical role in RA susceptibility and severity in North-east Indian cases and has prognostic significance in RA.

Three single nucleotide polymorphisms of TNFAIP3 gene increase the risk of rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic destructive inflammation in synovial joints. To date, many studies explored the associations between tumor necrosis factor alpha inducible protein 3 (TNFAIP3) gene rs6920220, rs2230926, and rs5029937 polymorphisms and the risk of rheumatoid arthritis (RA), but with contradictory results. We therefore conducted a comprehensive meta-analysis to address the associations. We searched in the databases of PubMed and Embase. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by the Stata 11.0 software. A total of 21 case-control studies for these three single nucleotide polymorphisms (SNPs) were included in this meta-analysis. Meta-analysis indicated that TNFAIP3 gene rs6920220, rs2230926, and rs5029937 polymorphisms were associated with the increased risk of RA. Stratification analysis of ethnicity found that rs6920220 and rs5029937 polymorphisms increased the risk of RA among Caucasians, while rs2230926 polymorphism increased the risk of RA among Asians. In summary, this meta-analysis confirms that TNFAIP3 gene polymorphisms may play important roles in the pathogenesis of RA.

NLRP1, PTPN22 and PADI4 gene polymorphisms and rheumatoid arthritis in ACPA-positive Singaporean Chinese

Studies have shown that the genetic risk factors for rheumatoid arthritis (RA) differ substantially between Asian and Caucasian populations. Even among Asian populations, the genetic contributions of NLRP1, PTPN22 and PADI4 have been controversial. Consequently, we sought to address these separate findings and determine whether any of these proposed risk variants are associated with RA susceptibility, onset, DAS activity and erosion in a Singaporean Chinese cohort. We genotyped five SNPs within NLRP1 (rs878329 and rs6502867), PTPN22 (rs2488457 and rs6665194), and PADI4 (rs2240340) in 500 anti-cyclic citrullinated peptide antibody-positive (ACPA) patients with RA and 500 healthy controls using TaqMan assays. The CC genotype of NLRP1 rs878329 and TT genotype of PADI4 rs2240340 were associated with RA susceptibility. The risk association of the T allele of PADI4 rs2240340 with RA was confirmed through a meta-analysis based on previous reports in Asian populations. The GG genotype of PTPN22 rs6665194 (-3508A>G) was associated with significantly reduced risk of RA. No significant association was found for NLRP1 rs6502867 T/C and PTPN22 rs2488457 G/C polymorphisms. None of the five SNPs was associated with RA's clinical features. This work supports the association of the T allele of PADI4 rs2240340 with RA in Asians. The roles of NLRP1 rs878329 G/C and PTPN22 rs6665194 A/G polymorphisms were demonstrated for the first time. We also propose rs6665194 to be a promising candidate for RA risk evaluation between ethnicities.

Associations between PTPN22 and TLR9 polymorphisms and systemic lupus erythematosus: a comprehensive meta-analysis

Previous studies have explored the relationship of PTPN22 and TLR9 polymorphisms with systemic lupus erythematosus (SLE). In consideration of the population stratification, conflicting results and updating data, we conducted a comprehensive meta-analysis, which consists of a total of 17 research articles (9120 cases and 11,724 controls) for PTPN22 and 20 articles (including up to 2808 cases and 3386 controls) for TLR9. Significant association was verified between PTPN22 rs2476601 and SLE in the overall population (OR = 1.511 per T allele, 95% CI 1.338-1.706, P = 2.931 × 10^-11) and under dominant model of T allele (TT+CT vs. CC: OR = 1.531, 95% CI 1.346-1.742, P = 9.17 × 10^-11). Analysis after stratification by ethnicity indicated that PTPN22 rs2476601 was related to SLE in Americans (OR = 2.566, 95% CI 1.796-3.665, P = 2.219 × 10^-7), Europeans (OR = 1.399, 95% CI 1.261-1.552, P = 2.153 × 10^-10), and Africans (OR = 4.14, 95% CI 1.753-9.775, P = 1.0 × 10^-3). We did not observe any association between TLR9 polymorphisms (rs187084, rs352140, rs5743836 and rs352139) and SLE under any model, after excluding the data that were inconsistent with Hardy-Weinberg equilibrium (HWE). In summary, PTPN22 rs2476601 was significantly interrelated with SLE and contributed to susceptibility and development of SLE in Americans, Europeans and Africans in this analysis, while their relationship needs to be validated in Africans by future research.

Searching Genome-Wide Multi-Locus Associations for Multiple Diseases Based on Bayesian Inference

Taking the advantage of high-throughput single nucleotide polymorphism (SNP) genotyping technology, large genome-wide association studies (GWASs) have been considered to hold promise for unraveling complex relationships between genotypes and phenotypes. Current multi-locus-based methods are insufficient to detect interactions with diverse genetic effects on multifarious diseases. Also, statistic tests for high-order epistasis ( ≥ 2 SNPs) raise huge computational and analytical challenges because the computation increases exponentially as the growth of the cardinality of SNPs combinations. In this paper, we provide a simple, fast and powerful method, named DAM, using Bayesian inference to detect genome-wide multi-locus epistatic interactions in multiple diseases. Experimental results on simulated data demonstrate that our method is powerful and efficient. We also apply DAM on two GWAS datasets from WTCCC, i.e., Rheumatoid Arthritis and Type 1 Diabetes, and identify some novel findings. Therefore, we believe that our method is suitable and efficient for the full-scale analysis of multi-disease-related interactions in GWASs.

Comorbidities of rheumatoid arthritis: Results from the Korean National Health and Nutrition Examination Survey

This study aimed to evaluate the prevalence of comorbidities in patients with rheumatoid arthritis (RA) compared with the non-RA population. The 2010-2012 Korea National Health and Nutrition Examination Survey (KNHANES), which assesses the general health status of populations in South Korea using interviews and basic health assessment, was analyzed retrospectively. Weighted prevalence and odds ratio (OR) of comorbidities were analyzed in patients with RA compared with the non-RA population. The overall weighted (n = 37,453,158) prevalence of RA was 1.5%. Patients with RA were older and more female predominant than subjects without RA. The prevalence of living in an urban area, college graduation, alcohol consumption and smoking was lower in patients with RA than non-RA. Patients with RA had more comorbidities including hypertension, dyslipidemia, myocardial infarction (MI) or angina, stoke, osteoarthritis, lung cancer, colon cancer, pulmonary tuberculosis, asthma, diabetes, depression, thyroid disease and chronic kidney disease. After adjusting socioeconomic and lifestyle characteristics, RA was associated with an increased prevalence of MI or angina (OR 1.86, 95% CI 1.17-2.96, p = 0.009), pulmonary TB (OR 1.95, 95% CI 1.24-3.09, p = 0.004), asthma (OR 1.97, 95% CI 1.05-3.71, p = 0.036), thyroid disease (OR 1.71, 95% CI 1.05-2.77), depression (OR 2.38, 95% CI 1.47-3.85, p < 0.001) and hepatitis B (OR 2.34, 95% CI 1.15-4.80, p = 0.020) compared with the non-RA population. Prevalence of solid cancer was not significantly associated with RA after adjustment.

TMEM187-IRAK1 Polymorphisms Associated with Rheumatoid Arthritis Susceptibility in Tunisian and French Female Populations: Influence of Geographic Origin

Polymorphisms have been identified in the Xq28 locus as risk loci for rheumatoid arthritis (RA). Here, we investigated the association between three polymorphisms in the Xq28 region containing TMEM187 and IRAK1 (rs13397, rs1059703, and rs1059702) in two unstudied populations: Tunisian and French. The rs13397 G and rs1059703 T major alleles were significantly increased in RA patients (n = 408) compared with age-matched controls (n = 471) in both Tunisian and French women. These results were confirmed by a meta-analysis replication study including two independent Greek and Korean cohorts. The rs1059702 C major allele was significantly associated with RA, only with French women. In the French population, the GTC haplotype displayed a protective effect against RA, while the ATC, GCC, and GTT haplotypes conferred significant risk for RA. No association for these haplotypes was found in the Tunisian population. Our results replicated for the first time the association of the three Xq28 polymorphisms with RA risk in Tunisian and French populations and suggested that RA susceptibility is associated with TMEM187-IRAK1 polymorphisms in women. Our data further support the involvement of X chromosome in RA susceptibility and evidence ethnicities differences that might be explained by differences in the frequencies of SE HLA-DRB1 alleles between both populations.

Association of CD40 Gene Polymorphisms with Susceptibility to Neuromyelitis Optica Spectrum Disorders

The CD40 gene is associated with many autoimmune diseases; however, there are few studies in literatures that investigate the association between CD40 and neuromyelitis optica spectrum disorders (NMOSD). This study aimed to estimate the potential association of CD40 gene polymorphisms with susceptibility to NMOSD. Four SNPs (rs1883832, rs3765459, rs4810485, and rs6074022) were selected and genotyped in a Chinese cohort comprising 162 patients with NMOSD and 237 healthy controls. P values, odds ratios (ORs), and 95 % confidential intervals (CI) for four test models (allelic, additive, dominant, and recessive) were used to assess relationships between CD40 and NMOSD. Results showed that the rs3765459 variant was significantly associated with increased risk of NMOSD in allelic model (OR = 1.48, 95 % CI 1.10-1.98, P = 0.009, P ^corr = 0.037), and similar results were detected in the additive and recessive models (OR = 1.47, 95 % CI 1.09-1.97, P = 0.010, P ^corr = 0.042; OR = 2.12, 95 % CI 1.18-3.8, P = 0.012, P ^corr = 0.048, respectively). Other three SNPs showed protections on NMOSD in dominant models (rs6074022, OR = 0.64, 95 % CI 0.42-0.95, P = 0.031; rs1883832, OR = 0.65, 95 % CI 0.43-0.97, P = 0.036; and rs4810485, OR = 0.63, 95 % CI 0.42-0.95, P = 0.029, respectively), but not significantly after Bonferroni corrections for multiple tests. In addition, haplotype analysis of these SNPs in tight linkage did not reveal significant association with NMOSD. This study indicates that the rs3765459 variant in CD40 gene is associated with susceptibility to NMOSD. Larger sample size studies in other ethnicities are needed to verify this association.

Evaluation of differences in HLA-DR4 gene and its subtypes prevalence among healthy people and RA patients in Isfahan province population

BACKGROUND

There are a lot of evidences showing that genetic play an important role in RA disease. Inheritance of some subgroups of HLA-DR4 gene increases the propensity to RA disease. In this paper, the impact of HLA-DR4 gene and its subtypes or subgroups, be consistence on RA patient who lived in Isfahan province, has been evaluated.

MATERIALS AND METHODS

In this survey, two groups of people (100 patients in case group and 100 normal persons in control group) have been selected. These two groups were similar in age and gender. Statistical population has been considered among people who visited Al Zahra rheumatology clinic. The participants were from Isfahan province and accepted to participate to the study voluntarily. The prevalence of HLA-DR4 and its 0401-0404 subtypes were evaluated between two groups; DNA was extracted from blood samples and studied using PCR SSCP method.

RESULTS

It was found that 35% of RA patients had HLA-DR4 gene, of which 14 persons had 0401, 10 persons had 0404, and 11 persons had other subtypes, whereas 30 people in control group had HLA-DR4 gene, of which 10 people had 0401, 20 people had 0404, and nobody had other subtypes.

CONCLUSION

The observed differences between prevalence of HLA-DR4 gene between the case and control group were not statistically significant (P = 0.45; OR = 1.256; 95% CI = 0.69-2.27), but a relation was between HLA-DR4 0404 subtypes and RA (P = 0.02; OR = 0.44; 95% CI = 0.196-0.992).

Meta-analysis reveals PTPN22 1858C/T polymorphism confers susceptibility to rheumatoid arthritis in Caucasian but not in Asian population

The PTPN22 1858C/T polymorphism is associated with rheumatoid arthritis (RA). However, reports from the Asian populations are conflicting in nature and lacks consensus. The aim of our study was to evaluate the association between the PTPN22 1858C/T polymorphism and RA in Asian and Caucasian subjects by carrying out a meta-analysis of Asian and Caucasian data. A total of 27 205 RA cases and 27 677 controls were considered in the present meta-analysis involving eight Asian and 35 Caucasian studies. The pooled odds ratios (ORs) were performed for the allele, dominant, and recessive genetic model. No statistically significant association was found between the PTPN22 1858C/T polymorphism and risk of RA in Asian population (allele genetic model: OR = 1.217, 95% confidence interval (CI) = 0.99-1.496, p value 0.061; dominant genetic model: OR = 1.238, 95% CI = 0.982-1.562, p value 0.071; recessive genetic model: OR = 1.964, 95% CI = 0.678-5.693, p value 0.213). A significant association with risk of RA in Caucasian population suggesting that T-- allele does confer susceptibility to RA in this subgroup was observed (allele genetic model: OR = 1.638, 95% CI = 1.574-1.705, p value < 0.0001; dominant genetic model: OR = 1.67, 95% CI = 1.598-1.745, p value < 0.0001; recessive genetic model: OR = 2.65, 95% CI = 2.273-3.089, p value < 0.0001). The PTPN22 1858C/T polymorphism is not associated with RA risk in Asian populations. However, our meta-analysis confirms that the PTPN22 1858C/T polymorphism is associated with RA susceptibility in Caucasians.

The dynamic evolution of rheumatology in Korea

Rheumatology was first recognized as a distinct clinical specialty in Korea just 35 years ago. Young professors who were trained in rheumatology in the USA and afterwards returned to Korea contributed substantially to advances in rheumatology clinical practice, educational programmes and research activities. They also established the Korean Rheumatism Association, later renamed the Korean College of Rheumatology. These young rheumatologists had a major role not only in raising the level of clinical and scientific activities, but also in promoting academic exchanges around the Asia-Pacific region, the USA and Europe. Subsequently, Korea's rapid economic growth and high education level enabled rheumatology to advance rapidly. Today, continued efforts are required to raise the standard of clinical and basic research, to optimize clinical practice with regard to new biologic agents, to exploit personalized and targeted therapies for the rheumatic diseases, and to meet the medical demands of Korea's ageing society.

Association of PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with rheumatoid arthritis: A meta-analysis update

BACKGROUND

Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The genes encoding protein tyrosine phosphatase non-receptor type 22 (PTPN22) and signal transducer and activator of transcription 4 (STAT4) have been reported to be associated with RA in several ethnic populations.

OBJECTIVES

This work aims to assess the association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility through an updated meta-analysis of available case-control studies.

METHODS

A literature search of all relevant studies published from January 2007 up to December 2014 was conducted using Pubmed and Science Direct databases. The observed studies that were related to an association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility were identified. Meta-analysis of the pooled and stratified data was done and assessed using varied genetic models.

RESULTS

Thirty-seven case-control studies with a total of 47 comparisons (29 for PTPN22 rs2476601 polymorphism and 18 for STAT4 rs7574865 polymorphism) met our inclusion criteria. The meta-analysis showed an association between PTPN22 T allele, CT+TT and TT genotypes with RA susceptibility. Furthermore, The meta-analysis showed an association between STAT4 T allele, GT+TT and TT genotypes with RA susceptibility. Stratification of RA patients according to ethnic groups showed that PTPN22 T allele, CT+TT genotypes, STAT4 T allele and STAT4 GT+TT were significantly associated with RA in European, Asian, African subjects, while PTPN22 TT genotype was significantly associated with RA in European but not in Asian and African subjects and STAT4 TT genotype was significantly associated with RA in European and Asian but not in African subject. A subgroup analysis according to the presence or absence of rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibodies revealed that the association between PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms with RA susceptibility may not be dependent on RF and anti-CCP antibodies.

CONCLUSIONS

Our meta-analysis demonstrated that PTPN22 rs2476601 and STAT4 rs7574865 polymorphisms confers susceptibility to RA in total subjects and in major ethnic groups. The association may not be dependent on RF and anti-CCP antibodies.

Associations between the functional CD40 rs4810485 G/T polymorphism and susceptibility to rheumatoid arthritis and systemic lupus erythematosus: a meta-analysis

Objective

The aim of this study was to determine whether the functional CD40 rs4810485 G/T polymorphism is associated with susceptibility to rheumatoid arthritis (RA) or with susceptibility to systemic lupus erythematosus (SLE).

Methods

A series of meta-analyses were conducted to test for association between the CD40 rs4810485 G/T polymorphism and RA or SLE.

Results

A total of 21 comparisons involving 15,095 patients and 27,050 controls for RA, and 1353 patients and 2342 controls for SLE were considered. Meta-analysis showed a significant association between the CD40 rs4810485 T allele and RA in all subjects (odds ratio (OR) 0.890, 95% confidence interval (CI) 0.846–0.936, p = 5.5 × 10−7). After stratification by ethnicity, the CD40 T allele was found to be significantly associated with RA in Europeans (OR 0.879, 95% CI 0.848–0.901, p = 3.0 × 10−9). A similar pattern of association was observed between the CD40 T allele and RA when the analysis was performed using the recessive, dominant, and additive models. Meta-analysis also showed a significant association between the CD40 polymorphism and SLE in Europeans (OR for the T allele 0.715, 95% CI 0.641–0.832, p = 1.4 × 10−6).

Conclusions

Our meta-analyses confirm that the CD40 rs4810485 G/T polymorphism is associated with susceptibility to RA and SLE in Europeans.

Positional identification of RT1-B (HLA-DQ) as susceptibility locus for autoimmune arthritis

Rheumatoid arthritis (RA) is associated with amino acid variants in multiple MHC molecules. The association to MHC class II (MHC-II) has been studied in several animal models of RA. In most cases these models depend on T cells restricted to a single immunodominant peptide of the immunizing Ag, which does not resemble the autoreactive T cells in RA. An exception is pristane-induced arthritis (PIA) in the rat where polyclonal T cells induce chronic arthritis after being primed against endogenous Ags. In this study, we used a mixed genetic and functional approach to show that RT1-Ba and RT1-Bb (RT1-B locus), the rat orthologs of HLA-DQA and HLA-DQB, determine the onset and severity of PIA. We isolated a 0.2-Mb interval within the MHC-II locus of three MHC-congenic strains, of which two were protected from severe PIA. Comparison of sequence and expression variation, as well as in vivo blocking of RT1-B and RT1-D (HLA-DR), showed that arthritis in these strains is regulated by coding polymorphisms in the RT1-B genes. Motif prediction based on MHC-II eluted peptides and structural homology modeling suggested that variants in the RT1-B P1 pocket, which likely affect the editing capacity by RT1-DM, are important for the development of PIA.

Assessment of protein tyrosine phosphatases number 22 polymorphism prevalence among rheumatoid arthritis patients: A study on Iranian patients

BACKGROUND

It has been proposed that Trp (620) allotype of protein tyrosine phosphatases number 22 (PTPN22) gene can intensify the susceptibility to rheumatoid arthritis (RA) and other autoimmune diseases. Thus, in this study, the prevalence of this polymorphism has been surveyed among RA patients compared with healthy persons. The samples were selected from Isfahan province (one of the most populated area of Iran).

MATERIALS AND METHODS

In this study, 100 patients (case group) and 100 healthy persons (control group) were participated voluntarily. The case group was selected from people who had referred to the rheumatology clinic of AlZahra University Hospital to follow-up their treatment and change their drugs dosage. The control group members, who were living in Isfahan province, mutually had similar age with patients. On a total, 22% of the case group was male and 75% of the control group was female. DNA was extracted from the blood sample of all cases and controls and the PTPN22 single nucleotide polymorphism (SNP) C1858> T gene polymorphism were studied using the polymerase chain reaction-restriction fragment length polymorphism method.

RESULTS

PTPN22 SNP C1858> T gene polymorphism was observed in 11 persons (11%) of the case group and 8 persons (8%) of the control group.

CONCLUSION

The results show that the difference was not statistically significant in Isfahan RA population (P = 0.47; OR = 1.42; 95% CI 0.55-3.69). Although, another study on Iranian population had shown that this polymorphism confers susceptibility to RA.

Trans-ethnic genome-wide association studies: advantages and challenges of mapping in diverse populations

Genome-wide association studies (GWASs) are the method most often used by geneticists to interrogate the human genome, and they provide a cost-effective way to identify the genetic variants underpinning complex traits and diseases. Most initial GWASs have focused on genetically homogeneous cohorts from European populations given the limited availability of ethnic minority samples and so as to limit population stratification effects. Transethnic studies have been invaluable in explaining the heritability of common quantitative traits, such as height, and in examining the genetic architecture of complex diseases, such as type 2 diabetes. They provide an opportunity for large-scale signal replication in independent populations and for cross-population meta-analyses to boost statistical power. In addition, transethnic GWASs enable prioritization of candidate genes, fine-mapping of functional variants, and potentially identification of SNPs associated with disease risk in admixed populations, by taking advantage of natural differences in genomic linkage disequilibrium across ethnically diverse populations. Recent efforts to assess the biological function of variants identified by GWAS have highlighted the need for large-scale replication, meta-analyses and fine-mapping across worldwide populations of ethnically diverse genetic ancestries. Here, we review recent advances and new approaches that are important to consider when performing, designing or interpreting transethnic GWASs, and we highlight existing challenges, such as the limited ability to handle heterogeneity in linkage disequilibrium across populations and limitations in dissecting complex architectures, such as those found in recently admixed populations.

RADB: a database of rheumatoid arthritis-related polymorphisms

Rheumatoid arthritis (RA) is an autoimmune disease that has a complex genetic basis. Therefore, it is important to explore the genetic background of RA. The extensive recent application of polymorphic genetic markers, especially single nucleotide polymorphisms, has presented us with a large quantity of genetic data. In this study, we developed the Database of Rheumatoid Arthritis-related Polymorphisms (RADB), to integrate all the RA-related genetic polymorphisms and provide a useful resource for researchers. We manually extracted the RA-related polymorphisms from 686 published reports, including RA susceptibility loci, polymorphisms associated with particular clinical features of RA, polymorphisms associated with drug response in RA and polymorphisms associated with a higher risk of cardiovascular disease in RA. Currently, RADB V1.0 contains 3235 polymorphisms that are associated with 636 genes and refer to 68 countries. The detailed information extracted from the literature includes basic information about the articles (e.g. PubMed ID, title and abstract), population information (e.g. country, geographic area and sample size) and polymorphism information (e.g. polymorphism name, gene, genotype, odds ratio and 95% confidence interval, P-value and risk allele). Meanwhile, useful annotations, such as hyperlinks to dbSNP, GenBank, UCSC, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway, are included. In addition, a tool for meta-analysis was developed to summarize the results of multiple studies. The database is freely available at http://www.bioapp.org/RADB.

Database URL:http://www.bioapp.org/RADB.

Immunochip identifies novel, and replicates known, genetic risk loci for rheumatoid arthritis in black South Africans

The aim of this study was to identify genetic variants associated with rheumatoid arthritis (RA) risk in black South Africans. Black South African RA patients (n = 263) were compared with healthy controls (n = 374). Genotyping was performed using the Immunochip, and four-digit high-resolution human leukocyte antigen (HLA) typing was performed by DNA sequencing of exon 2. Standard quality control measures were implemented on the data. The strongest associations were in the intergenic region between the HLA-DRB1 and HLA-DQA1 loci. After conditioning on HLA-DRB1 alleles, the effect in the rest of the extended major histocompatibility (MHC) diminished. Non-HLA single nucleotide polymorphisms (SNPs) in the intergenic regions LOC389203|RBPJ, LOC100131131|IL1R1, KIAA1919|REV3L, LOC643749|TRAF3IP2, and SNPs in the intron and untranslated regions (UTR) of IRF1 and the intronic region of ICOS and KIAA1542 showed association with RA (p < 5 × 10(-5)). Of the SNPs previously associated with RA in Caucasians, one SNP, rs874040, locating to the intergenic region LOC389203|RBPJ was replicated in this study. None of the variants in the PTPN22 gene was significantly associated. The seropositive subgroups showed similar results to the overall cohort. The effects observed across the HLA region are most likely due to HLA-DRB1, and secondary effects in the extended MHC cannot be detected. Seven non-HLA loci are associated with RA in black South Africans. Similar to Caucasians, the intergenic region between LOC38920 and RBPJ is associated with RA in this population. The strong association of the R620W variant of the PTPN22 gene with RA in Caucasians was not replicated since this variant was monomorphic in our study, but other SNP variants of the PTPN22 gene were also not associated with RA in black South Africans, suggesting that this locus does not play a major role in RA in this population.

Single nucleotide polymorphisms in TNFAIP3 were associated with the risks of rheumatoid arthritis in northern Chinese Han population

BACKGROUND

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by chronic destructive inflammation in synovial joints. It is well known that genetic and environmental risk factors and their interaction contribute to RA pathogenesis. This study aimed to investigate the association between the critical polymorphisms in the tumor necrosis factor α (TNFα)-induced protein 3(TNFAIP3) gene and the risk of RA in a large northern Chinese Han population.

METHODS

A case-control study of 1280 RA patients and 1280 matched healthy controls was conducted.

RESULTS

This study showed that carriers of the rs2230926 TG genotype or rs10499194 CT genotype had an increased risk for RA compared with those carrying the wild genotype (rs2230926: OR = 1.48, 95% CI = 1.17-1.86, p = 0.001; rs10499194: OR = 2.00, 95% CI = 1.46-2.74, p < 0.001). The combined rs2230926TG/GG or rs10499194 CT/TT were associated with an increased risk of RA (ORs were 1.50 and 2.01, 95% CIs were 1.19-1.88 and 1.47-2.74, respectively, both p < 0.001). There was not significant association between rs13207033 polymorphism and RA risk. Subset analysis stratified to gender showed that the increased risks were significant among the genotypes TG, TG/GG of rs2230926 and CT, CT/TT of rs10499194 and the corresponding ORs were 1.42 (95%  CI = 1.10-1.83, p = 0.006), 1.44(95% CI = 1.12-1.85, p = 0.004), 1.52(95% CI = 1.05-2.20, p = 0.026) and 1.52(95% CI = 1.06-2.19, p = 0.023) in the female population. Stratified analyses by age found that rs2230926(TG, TG/GG) and rs10499194(CT, CT/TT) polymorphisms were associated with RA risks in population ≤53 years old and among >53 years old only rs10499194(CT, TT, CT/TT) polymorphism had significant results. The interaction analysis suggested that individuals with both risk genotypes of the two SNPs have a higher elevated risk of RA than those with only one of them (ORs were 3.44 compared to 1.74 and 1.35). The haplotype results showed that individuals with the rs2230926G-rs13207033G-rs10499194C haplotype were associated with increased risks of RA (OR = 1.37, 95% CI = 1.08-1.74, p = 0.010).

CONCLUSIONS

Rs10499194 and rs2230926 polymorphisms in the TNFAIP3 gene region may be susceptibility factors for rheumatoid arthritis in the northern Chinese Han population.

A functional variant of PTPN22 confers risk for Vogt-Koyanagi-Harada syndrome but not for ankylosing spondylitis

BACKGROUND

Protein tyrosine phosphatase non-receptor 22 (PTPN22) is a key negative regulator of T lymphocytes and has emerged as an important candidate susceptibility factor for a number of immune-related diseases. This study aimed to examine the predisposition of PTPN22 SNPs to Vogt-Koyanagi-Harada (VKH) syndrome and acute anterior uveitis (AAU) associated with ankylosing spondylitis (AS).

METHODS

A total of 1005 VKH syndrome, 302 AAU+AS+ patients and 2010 normal controls among the Chinese Han population were enrolled in the study. Genotyping, PTPN22 expression, cell proliferation, cytokine production and cell activation were examined by PCR-RFLP, Real-time PCR, CCK8, ELISA and Flow cytometry.

RESULTS

The results showed significantly increased frequencies of the rs2488457 CC genotype and C allele but a decreased frequency of the GG genotype in VKH syndrome patients (PBonferroni correction (Pc) = 3.47×10(-7), OR = 1.54; Pc = 3.83×10(-8), OR = 1.40; Pc = 6.35×10(-4), OR = 0.62; respectively). No significant association of the tested SNPs with AAU+AS+ patients was observed. Functional studies showed a decreased PTPN22 expression, impaired cell proliferation and lower production of IL-10 in rs2488457 CC cases compared to GG cases (Pc = 0.009, Pc = 0.015 and Pc = 0.048 respectively). No significant association was observed concerning T cell activation and rs2488457 genotype.

CONCLUSIONS

The study showed that a functional variant of PTPN22 confers risk for VKH syndrome but not for AAU+AS+ in a Chinese Han population, which may be due to a modulation of the PTPN22 expression, PBMC proliferation and IL-10 production.

High-density genotyping of immune loci in Koreans and Europeans identifies eight new rheumatoid arthritis risk loci

OBJECTIVE

A highly polygenic aetiology and high degree of allele-sharing between ancestries have been well elucidated in genetic studies of rheumatoid arthritis. Recently, the high-density genotyping array Immunochip for immune disease loci identified 14 new rheumatoid arthritis risk loci among individuals of European ancestry. Here, we aimed to identify new rheumatoid arthritis risk loci using Korean-specific Immunochip data.

METHODS

We analysed Korean rheumatoid arthritis case-control samples using the Immunochip and genome-wide association studies (GWAS) array to search for new risk alleles of rheumatoid arthritis with anticitrullinated peptide antibodies. To increase power, we performed a meta-analysis of Korean data with previously published European Immunochip and GWAS data for a total sample size of 9299 Korean and 45,790 European case-control samples.

RESULTS

We identified eight new rheumatoid arthritis susceptibility loci (TNFSF4, LBH, EOMES, ETS1-FLI1, COG6, RAD51B, UBASH3A and SYNGR1) that passed a genome-wide significance threshold (p<5×10(-8)), with evidence for three independent risk alleles at 1q25/TNFSF4. The risk alleles from the seven new loci except for the TNFSF4 locus (monomorphic in Koreans), together with risk alleles from previously established RA risk loci, exhibited a high correlation of effect sizes between ancestries. Further, we refined the number of single nucleotide polymorphisms (SNPs) that represent potentially causal variants through a trans-ethnic comparison of densely genotyped SNPs.

CONCLUSIONS

This study demonstrates the advantage of dense-mapping and trans-ancestral analysis for identification of potentially causal SNPs. In addition, our findings support the importance of T cells in the pathogenesis and the fact of frequent overlap of risk loci among diverse autoimmune diseases.

Interaction of HLA-DRB1*09:01 and *04:05 with smoking suggests distinctive mechanisms of rheumatoid arthritis susceptibility beyond the shared epitope

OBJECTIVE

Although HLA-DRB1 shared epitope (SE) alleles and HLA-DRB1*09:01 have repeatedly been shown to be associated with susceptibility to rheumatoid arthritis (RA), the effect of each allele on levels of anticyclic citrullinated peptide autoantibodies (anti-CCP) and interaction with cigarette smoking in RA remains to be fully defined. We investigated whether HLA-DRB1 risk alleles influence anti-CCP levels and whether each allele interacts with smoking in anti-CCP-positive or -negative RA.

METHODS

All patients with RA (n = 1924) and controls (n = 1119) were Korean. The HLA-DRB1 4-digit genotyping was performed by standard PCR-sequencing based typing method. OR and biologic interactions as departures from additivity or multiplicity were analyzed by logistic regression.

RESULTS

SE alleles were significantly associated with increased anti-CCP levels. Conversely, HLA-DRB1*09:01 was associated with reduced levels, in both SE-positive and SE-negative patients. Each of SE alleles interacted significantly with smoking, whereas HLA-DRB1*09:01 did not. Interactions between the 2 most significant risk alleles, HLA-DRB1*04:05 and HLA-DRB1*09:01, (attributable proportion = 0.68, 95% CI 0.46-0.89, multiplicity p = 0.012) significantly increased RA susceptibility regardless of anti-CCP and smoking status. Smoking increased the risk for RA by significant interaction with the heterozygote HLA-DRB1*04:05/*09:01.

CONCLUSION

HLA-DRB1*09:01 differs from SE alleles with regard to anti-CCP levels and interaction with smoking, suggesting a distinct mechanism of HLA-DRB1*09:01 in the pathogenesis of RA that may bypass anti-CCP formation. Also, a significant increase of the HLA-DRB1*04:05/ *09:01 heterozygote in RA susceptibility may be attributable to the synergistic contribution of 2 different pathways in which 2 alleles participate independently.

The PTPN22 C1858T polymorphism and rheumatoid arthritis: a meta-analysis

The aim of this study was to determine whether the protein tyrosine phosphatase nonreceptor 22 (PTPN22) C1858T polymorphism confers susceptibility to rheumatoid arthritis (RA) in populations with different ethnicities. MEDLINE database and manual search were utilized to identify articles in which the PTPN22 polymorphism was determined in RA patients and controls. A meta-analysis was conducted on the associations between the PTPN22 C1858T polymorphism and RA using (1) allelic contrast and (2) dominant model. A total of 30 separate comparisons involving 17,961 RA patients and 18,611 controls were considered in this meta-analysis. Meta-analysis showed an association between the T allele and RA in all subjects (OR = 1.490, 95% CI = 1.332-1.668, P < 1.0 × 10(-9)). After stratification by ethnicity, analysis indicated that the T allele was significantly associated with RA in Europeans and in Non-Europeans (OR = 1.423, 95% CI = 1.260-1.605, P = 1.0 × 10(-8); OR = 1.902, 95% CI = 1.488-2.430, P = 2.8 × 10(-8)). Meta-analysis of the CT + TT genotype showed the same result patterns as that shown by the PTPN22 C1858T polymorphism T allele. Furthermore, a direct comparison between rheumatoid factor (RF)-positive and RF-negative subjects revealed a significant association with the T allele in RA patients with RF, but not in subjects without RF (OR = 1.561, 95% CI = 1.373-1.775, P < 1.0 × 10(-9)). This meta-analysis confirms that the PTPN22 C1858T polymorphism is associated with RA susceptibility in different ethnic groups, especially in Europeans, and the PTPN22 C1858T polymorphism T allele is significantly more prevalent in RF-positive patents than in RF-negative patients.

NF-κB and Rheumatoid Arthritis: Will Understanding Genetic Risk Lead to a Therapeutic Reward?

NF-κB has long been known to play an important role in autoimmune diseases such as rheumatoid arthritis (RA). Indeed, as our understanding of how NF-κB is utilized has increased, we have been hard put to find a process not associated with this transcription factor family in some way. However, new data originating, in part, from genome-wide association studies have demonstrated that very specific alterations in components of the NF-κB pathway are sufficient to confer increased risk of developing disease. Here we review the data which have identified specific components of the NF-κB pathway, and consider what is known of their mechanisms of action and how these mechanisms might play into the disease process. In addition, the use of genetic information to predict RA is considered.

The putative role of the C1858T polymorphism of protein tyrosine phosphatase PTPN22 gene in autoimmunity

Autoimmune diseases represent a heterogeneous group of conditions whose incidence is increasing worldwide. This has stimulated studies on their etiopathogenesis, derived from a complex interaction between genetic and environmental factors, in order to improve prevention and treatment of these diseases. An increasing amount of epidemiologic investigations has associated the presence of the C1858T polymorphism in the protein tyrosine phosphatase non-receptor type 22 (PTPN22) gene to the onset of several autoimmune diseases including insulin-dependent diabetes mellitus (Type 1 diabetes). PTPN22 encodes for the lymphoid tyrosine phosphatase Lyp. This belongs to non-receptor-type protein tyrosine phosphatases involved in lymphocyte activation and differentiation. In humans, Lyp may have a role in the negative regulation of T cell receptor signaling. The single nucleotide polymorphism C1858T encodes for a more active phosphatase Lyp R620W. This has the ability to induce a higher negative regulation of T cell receptor signaling. Thus, C1858T could play an important role at the level of thymocyte polarization and escape of autoreactive T lymphocytes, through the positive selection of otherwise negatively selected autoimmune T cells. In this review we discuss the physiological role exerted by the PTPN22 gene and its encoded Lyp product in lymphocyte processes. We highlight the pathogenic significance of the C1858T PTPN22 polymorphism in human autoimmunity with special reference to Type 1 diabetes. Recently the genetic variation in PTPN22 was shown to induce altered function of T and B-lymphocytes. In particular BCR signaling defects and alterations in the B cell compartment were reported in T1D patients. We finally speculate on the possible development of novel therapeutic treatments in human autoimmunity aiming to selectively target the variant Lyp protein in autoreactive T and B lymphocytes.

Association of genetic polymorphisms in CD40 with susceptibility to SLE in the Korean population

OBJECTIVE

The aim of this study was to examine the association of CD40 polymorphisms with the risk of SLE in the Korean population.

METHODS

A total of 601 Korean SLE patients and 984 healthy controls were enrolled. We selected seven CD40 gene SNPs based on previous results of CD40 gene sequencing in the Korean population. Statistical analysis was carried out by logistic regression, controlling for age and sex as covariates. Odds ratios (ORs) and P-values in co-dominant, dominant and recessive models were also calculated.

RESULTS

SNP rs3765456 showed significant association with risk of SLE (OR = 1.34, P = 0.007, Pcorr = 0.03) in the dominant model. SNPs rs1883832 and rs4810485, and haplotype 2 (GTTCTAA) were also associated with the risk of SLE in the dominant model, but statistical significance disappeared after correction for multiple testing. Haplotype 2 had a protective effect on LN (OR = 0.47, P = 0.01, Pcorr = 0.05) in the recessive model while rs73115010, rs6074028 and haplotype 3 (ACGTCGG) resulted in increased risk of arthritis in the recessive model (OR = 2.87, 2.76 and 2.46, P = 0.002, 0.004 and 0.01, Pcorr = 0.009, 0.02 and 0.05, respectively).

CONCLUSION

CD40 gene polymorphisms are possible risk factors for SLE development, especially rs3765456 in the dominant model. CD40 polymorphisms are also associated with SLE clinical manifestation, mainly nephritis and arthritis. Further replication with larger numbers, and populations of different ethnicities, are needed to confirm our findings.

A replication study confirms the association of dendritic cell immunoreceptor (DCIR) polymorphisms with ACPA - negative RA in a large Asian cohort

Objectives

Dendritic cell immunoreceptor (DCIR) has been implicated in development of autoimmune disorders in rodent and DCIR polymorphisms were associated with anti-citrullinated proteins antibodies (ACPA)-negative rheumatoid arthritis (RA) in Swedish Caucasians. This study was undertaken to further investigate whether DCIR polymorphisms are also risk factors for the development of RA in four Asian populations originated from China and Malaysia.

Methods

We genotyped two DCIR SNPs rs2377422 and rs10840759 in Han Chinese population (1,193 cases, 1,278 controls), to assess their association with RA. Subsequently, rs2377422 was further genotyped in three independent cohorts of Malaysian-Chinese subjects (MY_Chinese, 254 cases, 206 controls), Malay subjects (MY_ Malay, 515 cases, 986 controls), and Malaysian-Indian subjects (MY_Indian, 378 cases, 285 controls), to seek confirmation of association in various ethnic groups. Meta-analysis was preformed to evaluate the contribution of rs2377422 polymorphisms to the development of ACPA-negative RA in distinct ethnic groups. Finally, we carried out association analysis of rs2377422 polymorphisms with DCIR mRNA expression levels.

Results

DCIR rs2377422 was found to be significantly associated with ACPA -negative RA in Han Chinese (OR 1.92, 95% CI 1.27–2.90, P = 0.0020). Meta-analysis confirms DCIR rs2377422 as a risk factor for ACPA-negative RA across distinct ethnic groups (OR_overall = 1.17, 95% CI 1.06–1.30, P = 0.003). The SNP rs2377422 polymorphism showed significant association with DCIR mRNA expression level, i.e. RA-risk CC genotype exhibit a significant increase in the expression of DCIR (P = 0.0023, Kruskal–Wallis).

Conclusions

Our data provide evidence for association between DCIR rs2377422 and RA in non-Caucasian populations and confirm the influence of DCIR polymorphisms on RA susceptibility, especially on ACPA-negative RA.